Research Call

DAFM Reference

Lead(Collaborating)Institution

DAFM Award

Project Title:

An investigation of Verocytotoxigenic E. Coli super-shedding in beef and dairy cattle and the factors underpinning human virulence potential and strain emergence as a result of vt phage transduction

Project Coordinator:

Dr Geraldine Duffy

Project Abstract

Verocytotoxigenic E.coli (VTEC) is a serious food borne pathogen which can be shed in cattle faeces, providing a source of farm and food contamination. Much knowledge has been generated on this pathogen, but major gaps remain which hamper the development and implementation of effective control measures. Some cattle are reportedly “super-shedders” excreting exceptionally high numbers of VTEC, >10,000 CFU/g faeces, but the frequency and causes of this phenomenon are unknown. Such cattle have a disproportionately high impact on VTEC transmission into the beef and dairy chain and would be a key target for risk reduction measures. A further question in light of last years E. coli O104 outbreak strain is how to assess the human virulence potential of a VTEC isolated from animals or food. A set of virulence markers are needed which can be used to make a decision on the risk posed. The E. coli O104 outbreak strain had a unique virulence combination of Enteroaggregative E.coli (EAggEC) adherence genes and vt toxin instead on the usual vt and eae gene combination. It is vital to understand how vt genes, which are encoded on mobile genetic elements called bacteriophage, are persisting and transferring between VTEC and other bacteria in the farm environment leading to the potential emergence of another unusual and highly virulent VTEC. The proposed project will thus investigate three hot topics, (i) VTEC super-shedding in beef and dairy cattle and its impact on raw milk contamination; (ii) assessment of genetic markers which constitute a human virulent VTEC and (iii) the potential for emergence of new strains of VTEC as a result of phage transduction. This project addresses key issues related to VTEC along the complete chain (primary production, food and public health) and brings together researchers and stakeholders ensuring maximum impact for the project.